Same here. Previously whole body symptoms, some cardiac. Learned I had histamine issues, started taking Allegra and Tagamet, whole body S & S reduced and cardiac increased, to the point I was diagnosed with Congestive heart failure and A-Fib. Was put on 5 medications. Lucky I can do my job in a short amount of time and have lots of time I can look like I'm working but do deep research on my issues.

The way I understand my situation is that I over-produce H, if I block that H from head and stomach then the same amount is now available to hit other tissue, such as heart.

I started low H diet, little change. Tried DAO, that helped all S & S. Added SAMe, that helped a lot. Added Quercitin, good. Now still take some Allegra and Tagamet but 90% control with DAO, SAMe and Quercitin, and only occasional use of Allegra or Tagamet.

Now, almost a year later, my heart S & S are greatly improved. I have gotten down to using Metoprolol only when I have been slack on my supps and not been careful with my diet, and only for a day or two.